Water Quality and Availability

Introduction

Water Quality and Availability

Increased precipitation variability, shifts in seasonal runoff, climate trends, changes in watershed characteristics and water management decisions, increased demand for water, and changes in the economy are all factors that affect water quality and availability.

The Arbuckle-Simpson aquifer underlies about 500 square miles of south-central Oklahoma. It is an EPA designated, sole-source aquifer for the cities of Ada, Sulphur, Durant, and others in south-central Oklahoma, and is the source of water for a number of important springs and streams in the region. In response to local land owner proposals to transfer up to 80,000 acre-feet per year of Arbuckle-Simpson aquifer water to central Oklahoma for sale, the state passed Senate Bill 288 in 2003 and issued a moratorium on the issuance of water permits for the use of groundwater within the Arbuckle-Simpson aquifer. The Bill also directed the Oklahoma Water Resources Board (OWRB) to complete a detailed hydrologic study and approve a maximum annual yield that protects the natural flow of water from springs or streams emanating from the Arbuckle-Simpson aquifer. The study concluded in 2008 after years of public participation and technical analyses from dozens of agencies and organizations, including the Bureau of Reclamation, U.S. Geological Survey, Oklahoma Geological Survey, Oklahoma State University, and EPA’s National Risk Management Research Laboratory (NRMRL) in Ada, Oklahoma.

The OWRB is expected to make aquifer management recommendations in 2009. These water management strategies will be among many that are developed across the state as it finalizes its newly updated Comprehensive State Water Plan (CSWP). One such strategy being considered in Oklahoma’s CSWP is artificial aquifer storage and recharge. In 2008, the state passed Senate Bill 1410 and directed the OWRB to develop criteria to prioritize and recommend demonstration projects designed to recharge aquifers throughout the state. NRMRL’s Ada division is a member of a Governors Panel as specified in Senate Bill 1410.

The Chickasaw Nation encompasses a large portion of land over the Arbuckle-Simpson aquifer. In light of stresses placed on the Arbuckle-Simpson aquifer and Byrd’s Mill Spring from recent drought, the Chickasaw Nation is planning an aquifer storage and recharge (ASR) project to maintain and enhance spring flow at Byrd’s Mill Spring. NRMRL has an existing memorandum of understanding with the Chickasaw Nation (signed in 2008) to collaborate on such projects where possible. NRMRL’s Ground Water and Ecosystem Restoration Division began this collaboration in earnest in 2009 and received a Department of the Interior national award for this collaboration.

Climate change models predict potential decreased rainfall and increased evapotranspiration in the south-central and southwestern parts of the United States in coming decades. Water resource management will be needed to mitigate these effects. ASR has been demonstrated as an efficient way to conserve our water resources for future use and minimize losses in the short term. However, issues related to adverse water quality impacts to receiving aquifers have also been documented. EPA’s focus is to assist with the characterization of aquifers as candidates for recharge projects and assessment of water quality impacts from recharge.